Capacitor in semiconductor device and method of manufacturing the same

ABSTRACT

A capacitor may include at least one of a polysilicon layer over a semiconductor substrate; a capacitor dielectric layer over a polysilicon layer; an insulating layer over a capacitor dielectric layer; a metal layer connected to a capacitor dielectric layer through a first region of an insulating layer; an upper metal wiring layer connected to a metal layer over an insulating layer; and/or a lower metal wiring line layer connected to a polysilicon layer through a metal contact that passes through a second region of an insulating layer and a capacitor dielectric layer over the insulating layer.

The present application claims priority under 35 U.S.C. 119 and 35U.S.C. 365 to Korean Patent Application No. 10-2005-0127215 (filed onDec. 21, 2005), which is hereby incorporated by reference in itsentirety.

BACKGROUND

FIGS. 1 to 5 are sectional views illustrating a capacitor of asemiconductor device and a method of manufacturing the same. Asillustrated in FIG. 1, first polysilicon layer 120 may be formed oversemiconductor substrate 100 and insulating layer 110. Insulating layer110 may be a gate insulating layer. First polysilicon layer 120 may be agate conductive layer.

As illustrated in FIG. 2, first photoresist layer pattern 130 may beformed over first polysilicon layer 120. First photoresist layer 130 maypartially expose the surface of first polysilicon layer 120. A TEOSoxide layer may be arranged between first polysilicon layer 120 andfirst photoresist layer pattern 130. A TEOS oxide layer may be a cappinginsulating layer. DA ion implantation may be performed into an exposedportion of first polysilicon layer 120. After DA ion implantation, firstphotoresist layer pattern 130 may be removed.

As illustrated in FIG. 3, capacitor dielectric layer 140 may be formedover first polysilicon layer 120. Capacitor dielectric layer 140 mayhave an Oxide-Nitride-Oxide (ONO) structure. Capacitor dielectric layer140 may comprise lower oxide layer 141, nitride layer 142, and upperoxide layer 143. Second polysilicon layer 150 may be formed overcapacitor dielectric layer 140.

As illustrated in FIG. 4, second photoresist layer pattern 160 may beformed over second polysilicon layer 150. Second polysilicon layer 150may be etched using second photoresist layer pattern 160 as an etchingmask to form second polysilicon layer pattern 155. Capacitor dielectriclayer 140 may be etched using second photoresist layer pattern 160 as anetching mask to form capacitor dielectric layer pattern 145. Afterforming second polysilicon layer pattern 155 and/or capacitor dielectriclayer pattern 145, second photoresist layer pattern 160 may be removed.

As illustrated in FIG. 5, insulating layer 170 may be formed oversemiconductor substrate 100. First metal contact 181 and/or second metalcontact 182 may be formed in insulating layer 170. First metal contact181 may connect to second polysilicon layer pattern 155. Second metalcontact 182 may connect to first polysilicon layer 120. Upper metalwiring line layer 191 may be formed over first metal contact 181. Lowermetal wiring line layer 192 may be formed over second metal contact 182.

A capacitor having a polysilicon-dielectric layer-polysilicon structure(e.g. PIP structure) may include first polysilicon layer 120 as a lowerelectrode and second polysilicon layer pattern 155 as an upperelectrode. When forming a capacitor, a doped polysilicon layer may needto be deposited and etched, which may make a manufacturing processrelatively complicated. Complications maybe caused by particles, whichmay make it difficult to control processes.

SUMMARY

Embodiments relate to a semiconductor device and a method ofmanufacturing the same. Embodiments relate to a capacitor of asemiconductor device and a method of manufacturing the same. Embodimentsrelate to a capacitor of a semiconductor device with formation processesthat may be simplified by not having to deposit and etch a dopedpolysilicon layer.

In accordance with embodiments, a capacitor may include at least one ofa polysilicon layer over a semiconductor substrate; a capacitordielectric layer over a polysilicon layer; an insulating layer over acapacitor dielectric layer; a metal layer connected to a capacitordielectric layer through a first region of an insulating layer; an uppermetal wiring layer connected to a metal layer over an insulating layer;and/or a lower metal wiring line layer connected to a polysilicon layerthrough a metal contact that passes through a second region of aninsulating layer and a capacitor dielectric layer over the insulatinglayer. In embodiments, the width of a metal layer may be larger than thewidth of a metal contact.

Embodiments relate to a method that includes at least one of: forming apolysilicon layer over a semiconductor substrate; forming a capacitordielectric layer over a polysilicon layer; forming an insulating layerover a capacitor dielectric layer; removing a first region and a secondregion of an insulating layer to form a first contact hole and a secondhole that expose the surfaces of a first region and a second region of acapacitor dielectric layer; removing an exposed portion of a secondregion of a capacitor dielectric layer to partially expose the surfaceof a polysilicon layer; filling a first contact hole that partiallyexposes the surface of a capacitor dielectric layer and a second contacthole that partially exposes the surface of a polysilicon layer with ametal layer to form a metal layer in the first region and a metalcontact in the second region; and/or forming an upper metal wiring linelayer and a lower metal wiring line layer connected to a metal layer anda metal contact over an insulating layer.

In embodiments, a method includes implanting n-type impurity ions in apolysilicon layer after forming the polysilicon layer. In embodiments,the width of first contact hole is larger than the width of a secondcontact hole.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1 to 5 are sectional views illustrating a capacitor of asemiconductor device and a method of manufacturing the same.

Example FIGS. 6 to 11 are sectional views illustrating a capacitor of asemiconductor device and a method of manufacturing the same, accordingto embodiments.

DETAILED DESCRIPTION OF THE INVENTION

Example FIG. 11 is a sectional view illustrating a capacitor of asemiconductor device, according to embodiments. As illustrated in FIG.11, gate insulating layer 210 may be formed over semiconductor substrate200. Polysilicon layer 225 may be formed over gate insulating layer 210.Polysilicon layer 225 may serve as a lower electrode of a capacitor.Capacitor dielectric layer 245 may be formed over polysilicon layer 225.Capacitor dielectric layer 245 may comprise a silicon nitride layer(SiN).

In embodiments, capacitor dielectric layer 245 may have an ON(Oxide/Nitride) structure with an oxide layer and a nitride layersequentially laminated. In embodiments, capacitor dielectric layer 245may have an ONO (Oxide/Nitride/Oxide) structure with a lower oxidelayer, a nitride layer, and an upper oxide layer sequentially laminated.

Insulating layer 270 may be formed overcapacitor dielectric layer 245.Metal layer 255 (e.g. connected to capacitor dielectric layer 245through insulating layer 270) may be formed in a first region ofinsulating layer 270. Metal layer 255 may be used as an upper electrodeof a capacitor. Metal contact 282 (e.g. connected to polysilicon layer225 through insulating layer 270 and capacitor dielectric layer 245) maybe formed in a second region of insulating layer 270. The width of metallayer 255 may be larger than the width of metal contact 282, which maybe tailored to the desired capacitance of a capacitor. Upper metalwiring layer 291 may be formed over metal layer 255. Lower metal wiringlayer 292 may be formed over metal contact 282.

In embodiments, a capacitor may have a PIN (Polysilicon/Insulator/Metal)structure with lamination of polysilicon layer 225 as a lower electrode,capacitor dielectric layer 245, and metal layer 255 as an upperelectrode. IN embodiments, electrical characteristics may be improvedfrom embodiments where a polysilicon layer is used as an upperelectrode.

Examples FIGS. 6 to 10 are sectional views illustrating a method ofmanufacturing a capacitor of a semiconductor device, according toembodiments. As illustrated in FIG. 6, gate insulating layer 210 andpolysilicon layer 220 may be sequentially formed over semiconductorsubstrate 200. Gate insulating layer 210 may comprise an oxide layer.Polysilicon layer 220 may serve as a lower electrode of a capacitor.Polysilicon layer 220 may be formed in the same processing step as theformation of a gate conductive layer in another region of semiconductor200.

As illustrated in FIG. 7, common patterning may be performed to removeportions of gate insulating layer 210 and polysilicon layer 220, inaccordance with embodiments. A side wall spacer layers 310 may be formedon side walls of gate insulating layer 210 and polysilicon layer 220.N-type impurity ions may be implanted to dope polysilicon layer 220, asillustrated in FIG. 7. In embodiments, the resistance of polysiliconlayer 220 may be reduced by implantation of n-type impurity ionscompared to DA ion implantation in other embodiments.

As illustrated in FIG. 8, capacitor dielectric layer 245 may be formedover semiconductor substrate 200. Capacitor dielectric layer 245 mayinclude SiN. In embodiments, capacitor dielectric layer 245 may have anON (Oxide/Nitride) structure with an oxide layer and a nitride layersequentially laminated. In embodiments, capacitor dielectric layer 245may have an ONO (Oxide/Nitride/Oxide) structure with a lower oxidelayer, a nitride layer, and an upper oxide layer sequentially laminated.

As illustrated in FIG. 9, insulating layer 270 may be formed overcapacitor dielectric layer 245. First photoresist layer pattern 230 maybe formed over insulating layer 270. Insulating layer 270 may be etchedfirst photoresist layer pattern 230 as an etching mask to remove exposedportions of insulating layer 270. In a first region of insulating layer270, a first trench may expose a surface of capacitor dielectric layer245. In a second region of insulating layer 270, a second trench mayexpose capacitor dielectric layer 245. A first trench may be formed foran upper electrode of a capacitor. A second trench may be formed for ametal contact for connecting a lower electrode of a capacitor and alower metal wiring line layer. In embodiments, the width of a firsttrench may be larger than the width of a second trench. In embodiment,the width of the first trench and/or the second trench is determined inaccordance with a desired capacitance of a capacitor. After forming afirst trench and a second trench, first photoresist layer pattern 230may be removed.

As illustrated in FIG. 10, second photoresist layer pattern 260 may beformed in a first trench and over insulating layer 270, in accordancewith embodiments. Second photoresist layer pattern 260 may expose asurface of capacitor dielectric layer 245 at the bottom of a secondtrench. An etching process may be performed on capacitor dielectriclayer 245 at the bottom of a second trench using second photoresistlayer pattern 260 as an etching mask to expose a portion of polysiliconlayer 225 at the bottom of a second trench. Second photoresist layerpattern 260 may be removed after removing capacitor dielectric layer 245at the bottom of a second trench.

As illustrated in FIG. 11, metal layer 255 and metal contact 282 may beformed in a first trench and a second trench. Metal layer 255 mayelectrically contact a surface of capacitor dielectric layer 245, inembodiments. Metal contact 282 may electrically contact a surface ofpolysilicon layer 225, in embodiments. Metal layer 255 may serve as anupper electrode of a capacitor, in accordance with embodiments. Uppermetal wiring line layer 291 and/or lower metal wiring line layer 292 maybe formed over metal layer 255 and metal contact 282.

In embodiments, a capacitor may be formed by n-type impurity ionimplantation instead of DA ion implantation. In embodiments, a metallayer may serve as ab upper electrode instead of a doped polysiliconlayer. In accordance with embodiments, a process of forming a capacitormay be relatively simple. In embodiments, generation of particles may besubstantially prevented and/or minimized.

While the invention has been shown and described with reference tocertain preferred embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

1. A method of forming a capacitor comprising: forming a polysiliconlayer over a semiconductor substrate; forming a capacitor dielectriclayer over the polysilicon layer; forming a metal layer over thecapacitor dielectric layer; forming an insulating layer over thecapacitor dielectric layer; forming a first contact hole in theinsulating layer, wherein the metal is formed in the first contact hole;and forming a second contact hole in the insulating layer and thecapacitor dielectric layer, wherein the second contact hole is in adifferent region than the first contact hole, wherein the first contacthole and a portion of the second contact hole in the insulating layerare formed at substantially the same time, wherein a portion of thesecond contact hole in the capacitor dielectric layer is formed afterforming the second contact hole through the insulating layer, wherein anetching mask is formed over the first contact hole before forming theportion of the second contact hole in the capacitor dielectric layer,and wherein the etching mask is removed after forming the portion of thesecond contact hole in the capacitor dielectric layer.
 2. The method ofclaim 1, comprising forming a metal contact in the second contact hole.3. The method of claim 1, wherein the width of the first contact hole islarger than the width of the second contact hole.
 4. The method of claim1, wherein: the polysilicon layer is a lower capacitor electrode; andthe metal layer is an upper capacitor electrode.
 5. The method of claim1, comprising implanting n-type impurity ions in the polysilicon layer.